Delving into massive stars: the colliding wind binaries, relations and various interferometric radio observations

Zainol, Farrah Dilla (2021). Delving into massive stars: the colliding wind binaries, relations and various interferometric radio observations. University of Birmingham. Ph.D.

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Massive stars are rare and possess strong winds that provide feedback mechanisms to the interstellar medium. They are usually found in binary or multiple systems, which complicates the wind interaction between stars. This work has primarily involved massive stars, focusing on the colliding-wind binary at radio wavelengths as well as other wavelengths, such as the X-ray. A new Güdel-Benz style relation uncovered in an archival sample of massive stars suggests a positive correlation between X-ray and radio luminosities.

Several new radio observations of the archetypal colliding-wind binary WR140 at low and high frequencies have been made using the currently available radio interferometers. The low frequencies radio observations using the upgraded broad bandwidth Giant Metre Radio Telescope at 0.3−1.4 GHz revealed that WR140 has a thermal spectrum, a vital baseline to disentangle the non-thermal emission in future works. The high-frequency radio observation of WR140 at 22 GHz to observe the colliding wind region closer to apastron was unsuccessful due to the high rms of the East Asia Very Large Baseline Interferometer Network (EAVN).

We introduced the Distributed Radio Emission Measure model to capture the shape of the non-thermal radio emission spectra from various archival WR140 radio data. The outcomes of the model indicate that the radio emission from the wind collision region is the result of a distributed emission measure, where the line-of-sight has travelled across different regions. The radio emission measure is large at apastron consistent with thermal emission and progressively small leading up to periastron, revealing the non-thermal emission region, coherent with the observational radio data.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Physics and Astronomy
Funders: Other
Other Funders: MARA Malaysia
Subjects: Q Science > QB Astronomy


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